JPH021978B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection method suitable for measuring the relative timing of fuel injection into a combustion chamber of a diesel engine or a gasoline engine by a fuel injection device with respect to a crank rotation angle. This invention relates to a timing measuring device.

[Prior Art] Conventionally, fuel injection timing is measured through detection of pressure changes in a high-pressure pipe that leads fuel from an injection pump to an injection nozzle, or through movement of a detection wire attached to a needle valve of an injection nozzle. Measuring.

[Problems to be Solved by the Invention] However, the former method cannot accurately measure the injection timing due to the existence of a delay between the rise in pressure in the high-pressure pipe and the opening of the needle valve; In this method, it is necessary to cut open the nozzle body in order to take out the detection wire attached to the needle valve.

An object of the present invention is to provide a fuel injection timing measuring device that can accurately measure fuel injection timing with a simple structure.

[Means for Solving the Problems] The present invention provides a fuel injection timing measuring device for measuring when fuel is injected into a combustion chamber of an internal combustion engine by an injection nozzle including a nozzle body and a needle valve. Alternatively, the needle valve is magnetized and a coil is attached to the outer periphery of the fuel discharge port of the nozzle body.

[Operation] According to the present invention, the movement timing of the needle valve during fuel injection is detected as a change in coil terminal voltage based on a change in magnetic flux passing through the coil, and the fuel injection timing can be measured.

At this time, in the present invention, since the coil is attached to the outer periphery of the fuel discharge port of the nozzle body,
Compared to the case where the coil is installed around parts that are subject to relative displacement with the fuel discharge port opening/closing part of the needle valve, such as the outer periphery of the spring seat that contacts the upper end of the needle valve or the outer periphery of the upper end of the needle valve. , it is possible to accurately measure the timing of fuel injection from the fuel discharge port without delay. That is, the fuel injection timing can be accurately measured with a simple structure.

[Embodiment] FIG. 1 is a partial sectional view showing the main part of an embodiment of the present invention, and shows a state in which an injection nozzle 11 is installed in a mounting hole 13 formed in a cylinder head 12 of a diesel engine. It shows. The injection nozzle 11 houses a nozzle body 15 and a needle valve 16 in a retaining nut 14 that can be screwed into a mounting hole 13, and a nozzle holder 17 is integrated into the upper part of the retaining nut 14. The biasing force of a spring 18 housed therein acts on the needle valve 16 via a damper 19, allowing the needle valve 16 to close the fuel discharge port of the nozzle body 15. The injection nozzle 11 is mounted with a gasket 20 interposed between the tip end surface of the nozzle body 15 and the finished bottom surface of the mounting hole 13 of the cylinder head 12. When high pressure fuel is delivered from the injection pump through the high pressure pipe, the nozzle holder 17,
Retaining nut 14 and nozzle body 15
The fuel is fed under pressure to the fuel reservoir in the nozzle body 15 through the fuel passage 21 formed continuously in the fuel passageway 21, and when the oil pressure overcomes the biasing force of the spring 18, the needle valve 16 is pushed up against the nozzle body 15, and the fuel is pumped up. Injection into the combustion chamber can now begin.

Here, the nozzle body 1 of the injection nozzle 11
5 and the needle valve 16 are magnetized, and a coil 2 is attached to the outer periphery of the fuel discharge port of the nozzle body 15.
2 is installed. The coil 22 is molded into a ring shape with resin, and when installed in the installation hole 13 of the injection nozzle 11, the retaining nut 1 is
4 and the gasket 20,
The nozzle body 15 is in such a state that it does not freely vibrate even when the engine is operating. The coil terminal 23 of the coil 22 can be taken out to the outside through a passage defined by a take-out groove 24 formed in the retaining nut 14 and a threaded portion of the attachment hole 13. That is, when the needle valve 16 moves relative to the nozzle body 15 at the injection timing, a current proportional to the moving speed of the needle valve 16 flows through the coil 22 due to electromagnetic induction. Therefore, as shown in FIG. 2, the coil 22 has a terminal voltage E that is synchronized with the change in the lift L of the needle valve 16 with respect to the crank rotation axis θ, that is, the injection timing, and is proportional to the moving speed of the needle valve 16. occurs.

Coil 2 generated in synchronization with the above fuel injection timing
The terminal voltage of amplifier 2 is as shown in FIG.
5 and causes the timing light 26 to emit strobe light. The strobe light emitted from the timing light 26 illuminates the angle scale attached to the flywheel magneto of the crankshaft and the reference mark on the crankcase side, making it possible to measure the crank rotation angle at that point in time, that is, the fuel injection timing. .

According to the above embodiment, fuel is discharged from the injection pump, the needle valve 16 is moved by the oil pressure, and injection in the combustion chamber is started.At the same time, the change in the magnetic flux passing through the coil 22 causes the coil 22
A terminal voltage is generated, and the timing light 26 emits a strobe light due to the terminal voltage, and by illuminating the angle scale on the crankshaft side and the reference mark on the crankcase side, the crank rotation angle at the time of the terminal voltage change is determined. , that is, the fuel injection timing is measured.

At this time, in the above embodiment, since the coil 22 is attached to the outer periphery of the fuel discharge port of the nozzle body 15, the coil 22 is connected to the needle valve 16.
Those needle valves 16 such as the outer periphery of the spring seat that comes into contact with the upper end and the outer periphery of the upper end of the needle valve 16
The timing of fuel injection from the fuel discharge port can be accurately measured without delay compared to the case where the device is mounted around a part that is subject to relative displacement between the fuel discharge port opening and closing portion of the fuel discharge port.

Therefore, according to the above embodiment, the nozzle body 15 and the needle valve 16 are magnetized without cutting the injection nozzle 11, and the nozzle body 1
The simple structure of simply mounting the coil 22 on the outer periphery of the tip of the fuel injection valve 5 makes it possible to accurately measure the fuel injection timing. Note that the coil terminal voltage signal can also be used to operate an electric timer or the like that electrically adjusts the timing of fuel injection.

Note that the change in the terminal voltage of the coil 22 based on the movement of the needle valve 16 is based on the change in the magnetic flux passing through the coil 22. Therefore, if both the nozzle body 15 and the needle valve 16 are at least magnetic, the above It is not necessary to magnetize both the nozzle body 15 and the needle valve 16 as in the embodiment, and only one of them may be magnetized. When magnetizing only the nozzle body 15, it is possible to easily magnetize the nozzle body 15 by simply rubbing the end face of the nozzle body 15 of the assembled injection nozzle 11 against a magnet.

Further, the coil 22 may be molded with resin inside a metal case and attached to the outer peripheral portion of the tip of the nozzle body 15.

Further, in the above embodiment, a case has been described in which the timing light 26 is used to measure the crank rotation angle at the fuel timing, but as shown in FIG.
The signal waveform that displays and the terminal voltage E of the coil 22
Simultaneously observe the signal waveform that displays changes in the
The advance angle T of the terminal voltage change timing with respect to the top dead center θ _TOP , that is, the injection timing may be observed. Note that the signal indicating the crank rotation angle θ in this case can be extracted by an electromagnetic pickup mounted around the crankshaft.

[Effects of the Invention] As described above, according to the present invention, injection timing can be accurately measured with a simple structure.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing the main part of an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the crank rotation angle, the movement lift of the needle valve, and the coil terminal voltage in the same embodiment, and FIG. The figure is an electric circuit diagram showing injection timing detection means using a timing light in the same embodiment, and FIG. 4 is an explanatory diagram showing injection timing detection means using an oscilloscope. 11... Injection nozzle, 15... Nozzle body,
16... Needle valve, 22... Coil, 26
...timing light.

Claims (1)

[Claims] 1. In a fuel injection timing measurement device that measures when fuel is injected into a combustion chamber of an internal combustion engine by an injection nozzle that includes a nozzle body and a needle valve, the nozzle body and/or needle valve is magnetized and the fuel discharge port of the nozzle body is A fuel injection timing measuring device characterized by a coil attached to the outer periphery.